Project description:<p>In this study, patients with advanced cancer across all histologies were enrolled in our IRB approved clinical sequencing program, called MI-ONCOSEQ, to go through an integrative sequencing which includes whole exome sequencing of the tumor and matched normal, and transcriptome sequencing. Four index cases were identified which harbor gene rearrangements of FGFR2 including two cholangiocarcinoma cases, a metastatic breast cancer case, and a metastatic prostate cancer case. After extending our assessment of FGFR rearrangements across multiple tumor cohorts, including TCGA, we identified FGFR gene fusions with intact kinase domains of FGFR1, FGFR2, or FGFR3 in cholangiocarcinoma, breast cancer, prostate cancer, lung squamous cell cancer, bladder cancer, thyroid cancer, oral cancer, glioblastoma, and head and neck squamous cell cancer. All FGFR fusion partners tested exhibit oligomerization capability, suggesting a shared mode of kinase activation. Overexpression of FGFR fusion proteins in vitro induced cell proliferation, and bladder cancer cell lines that harbors FGFR3 fusion proteins exhibited enhanced susceptibility to pharmacologic inhibition in vitro and in vivo. Due to the combinatorial possibilities of FGFR family fusion to a variety of oligomerization partners, clinical sequencing efforts which incorporate transcriptome analysis for gene fusions are poised to identify rare, targetable FGFR fusions across diverse cancer types.</p>
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:By combining extensive biochemical fractionation with quantitative mass spectrometry, we directly examined the composition of soluble multiprotein complexes among diverse animal models. The project has been jointly supervised by Andrew Emili and Edward M. Marcotte. Project website: http://metazoa.med.utoronto.ca
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
Project description:We first verified that erdafitinib is synergistic with quisinostat in vitro and confirmed that the combinational treatment can significantly enhance the inhibition of tumor growth and prolong the survival in vivo for bladder cancers with FGFR3 fusions. Next, in order to understand the underlying molecular mechanisms of this synergy, we performed RNA-seq analysis. We revealed that quisinostat can concomitantly inhibit FGFR signaling with erdafitinib by suppressing the translation of FGFR3 fusions. In addition, quisinostat can also sensitize bladder cancer cells to erdafitinib by downregulating HDGF, which is a second mechanism of the synergy independent of FGFR signaling.
Project description:A subset of triple negative breast cancers (TNBC) are characterized by genetic alterations in fibroblast growth factor receptors (FGFR) including amplifications, activating mutations or gene fusions. However, despite this genetic evidence of FGFR-dependency, FGFR inhibitors have shown only limited clinical efficacy in TNBC, suggesting the presence of intrinsic or adaptive resistance mechanisms. Using genome-wide CRISPR screens, we found that resistance to FGFR inhibition is mediated by activation of the mTORC1 and YAP pathways. Prolonged FGFR inhibition increased expression of several amino acid transporters resulting in increased cellular level of certain amino acids and activation of the mTORC1 amino acid sensing pathway. Epigenomic analyses revealed that FGFR inhibition reorganized YAP/TEAD associated enhancers leading to the upregulation of YAP target genes including the amino acid transporters upstream of mTORC1. Remarkably, mTORC1 and FGFR inhibitors synergistically blocked the growth of TNBC cells in vitro and in patient-derived xenografts. These findings define a novel epigenetic feedback mechanism involving intracellular amino acid levels leading to targeted therapy resistance in TNBC, and offers a combinatorial drug treatment strategy to improve clinical outcomes for this aggressive breast cancer subtype.
Project description:A subset of triple negative breast cancers (TNBC) are characterized by genetic alterations in fibroblast growth factor receptors (FGFR) including amplifications, activating mutations or gene fusions. However, despite this genetic evidence of FGFR-dependency, FGFR inhibitors have shown only limited clinical efficacy in TNBC, suggesting the presence of intrinsic or adaptive resistance mechanisms. Using genome-wide CRISPR screens, we found that resistance to FGFR inhibition is mediated by activation of the mTORC1 and YAP pathways. Prolonged FGFR inhibition increased expression of several amino acid transporters resulting in increased cellular level of certain amino acids and activation of the mTORC1 amino acid sensing pathway. Epigenomic analyses revealed that FGFR inhibition reorganized YAP/TEAD associated enhancers leading to the upregulation of YAP target genes including the amino acid transporters upstream of mTORC1. Remarkably, mTORC1 and FGFR inhibitors synergistically blocked the growth of TNBC cells in vitro and in patient-derived xenografts. These findings define a novel epigenetic feedback mechanism involving intracellular amino acid levels leading to targeted therapy resistance in TNBC, and offers a combinatorial drug treatment strategy to improve clinical outcomes for this aggressive breast cancer subtype.
Project description:Chromosomal rearrangements and gene fusions are the initial events in the development of many cancers. Astroblastoma (ABM), a challenging brain cancer of unknown cellular origin, is associated with diverse in-frame gene fusions, including MN1:BEND2 and MN1:CXXC5. However, it remains unclear if these gene fusions contribute to tumorigenesis. Here, we show that the two ABM-associated fusions converge on similar molecular activities and initiate malignancy specifically in ventral telencephalon neural progenitors. BEND2 and CXXC5 recognized similar DNA motifs, suggesting a convergence on downstream gene regulation. Expressing MN1:BEND2 in ventral telencephalon neural progenitors results in aberrant cell proliferation, impaired differentiation, a perivascular occupancy pattern of cells reminiscent of ABM, and acquisition of an ABM-associated transcriptional signature. In stark contrast, MN1:BEND2 expression in dorsal telencephalon neural progenitors leads to extensive cell death. This cell-type specific malignancy is dependent on Olig2 expression. Mechanistically, both ABM-associated fusion proteins (MN1:BEND2 and MN1:CXXC5) induce overlapping transcriptional responses, including the activation of a therapeutically targetable PDGFRα pathway. Collectively, our data suggests that distinct ABM-associated fusions upregulate shared transcriptional networks, thereby disrupting the normal development of ventral telencephalon neural progenitors and culminating in oncogenic transformation. These findings uncover new avenues for targeted ABM treatment.